Package edu.wpi.first.wpilibj

Class Preferences

java.lang.Object
edu.wpi.first.wpilibj.Preferences
public final class Preferences
extends Object
The preferences class provides a relatively simple way to save important values to the roboRIO to access the next time the roboRIO is booted.

This class loads and saves from a file inside the roboRIO. The user can not access the file directly, but may modify values at specific fields which will then be automatically saved to the file by the NetworkTables server.

This class is thread safe.

This will also interact with NetworkTable by creating a table called "Preferences" with all the key-value pairs.

  • Method Summary

    Modifier and Type Method Description
    static boolean containsKey​(String key)
    Returns whether there is a key with the given name.
    static boolean getBoolean​(String key, boolean backup)
    Returns the boolean at the given key.
    static double getDouble​(String key, double backup)
    Returns the double at the given key.
    static float getFloat​(String key, float backup)
    Returns the float at the given key.
    static int getInt​(String key, int backup)
    Returns the int at the given key.
    static Collection<String> getKeys()
    Gets the preferences keys.
    static long getLong​(String key, long backup)
    Returns the long at the given key.
    static String getString​(String key, String backup)
    Returns the string at the given key.
    static void initBoolean​(String key, boolean value)
    Puts the given boolean into the preferences table if it doesn't already exist.
    static void initDouble​(String key, double value)
    Puts the given double into the preferences table if it doesn't already exist.
    static void initFloat​(String key, float value)
    Puts the given float into the preferences table if it doesn't already exist.
    static void initInt​(String key, int value)
    Puts the given int into the preferences table if it doesn't already exist.
    static void initLong​(String key, long value)
    Puts the given long into the preferences table if it doesn't already exist.
    static void initString​(String key, String value)
    Puts the given string into the preferences table if it doesn't already exist.
    static void remove​(String key)
    Remove a preference.
    static void removeAll()
    Remove all preferences.
    static void setBoolean​(String key, boolean value)
    Puts the given boolean into the preferences table.
    static void setDouble​(String key, double value)
    Puts the given double into the preferences table.
    static void setFloat​(String key, float value)
    Puts the given float into the preferences table.
    static void setInt​(String key, int value)
    Puts the given int into the preferences table.
    static void setLong​(String key, long value)
    Puts the given long into the preferences table.
    static void setNetworkTableInstance​(NetworkTableInstance inst)
    Set the NetworkTable instance used for entries.
    static void setString​(String key, String value)
    Puts the given string into the preferences table.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • setNetworkTableInstance

      public static void setNetworkTableInstance​(NetworkTableInstance inst)
      Set the NetworkTable instance used for entries. For testing purposes; use with caution.
      Parameters:
      inst - NetworkTable instance

    • getKeys

      public static Collection<String> getKeys()
      Gets the preferences keys.
      Returns:
      a collection of the keys

    • setString

      public static void setString​(String key, String value)
      Puts the given string into the preferences table.
      Parameters:
      key - the key
      value - the value
      Throws:
      NullPointerException - if value is null

    • initString

      public static void initString​(String key, String value)
      Puts the given string into the preferences table if it doesn't already exist.
      Parameters:
      key - The key
      value - The value

    • setInt

      public static void setInt​(String key, int value)
      Puts the given int into the preferences table.
      Parameters:
      key - the key
      value - the value

    • initInt

      public static void initInt​(String key, int value)
      Puts the given int into the preferences table if it doesn't already exist.
      Parameters:
      key - The key
      value - The value

    • setDouble

      public static void setDouble​(String key, double value)
      Puts the given double into the preferences table.
      Parameters:
      key - the key
      value - the value

    • initDouble

      public static void initDouble​(String key, double value)
      Puts the given double into the preferences table if it doesn't already exist.
      Parameters:
      key - The key
      value - The value

    • setFloat

      public static void setFloat​(String key, float value)
      Puts the given float into the preferences table.
      Parameters:
      key - the key
      value - the value

    • initFloat

      public static void initFloat​(String key, float value)
      Puts the given float into the preferences table if it doesn't already exist.
      Parameters:
      key - The key
      value - The value

    • setBoolean

      public static void setBoolean​(String key, boolean value)
      Puts the given boolean into the preferences table.
      Parameters:
      key - the key
      value - the value

    • initBoolean

      public static void initBoolean​(String key, boolean value)
      Puts the given boolean into the preferences table if it doesn't already exist.
      Parameters:
      key - The key
      value - The value

    • setLong

      public static void setLong​(String key, long value)
      Puts the given long into the preferences table.
      Parameters:
      key - the key
      value - the value

    • initLong

      public static void initLong​(String key, long value)
      Puts the given long into the preferences table if it doesn't already exist.
      Parameters:
      key - The key
      value - The value

    • containsKey

      public static boolean containsKey​(String key)
      Returns whether there is a key with the given name.
      Parameters:
      key - the key
      Returns:
      if there is a value at the given key

    • remove

      public static void remove​(String key)
      Remove a preference.
      Parameters:
      key - the key

    • removeAll

      public static void removeAll()
      Remove all preferences.

    • getString

      public static String getString​(String key, String backup)
      Returns the string at the given key. If this table does not have a value for that position, then the given backup value will be returned.
      Parameters:
      key - the key
      backup - the value to return if none exists in the table
      Returns:
      either the value in the table, or the backup

    • getInt

      public static int getInt​(String key, int backup)
      Returns the int at the given key. If this table does not have a value for that position, then the given backup value will be returned.
      Parameters:
      key - the key
      backup - the value to return if none exists in the table
      Returns:
      either the value in the table, or the backup

    • getDouble

      public static double getDouble​(String key, double backup)
      Returns the double at the given key. If this table does not have a value for that position, then the given backup value will be returned.
      Parameters:
      key - the key
      backup - the value to return if none exists in the table
      Returns:
      either the value in the table, or the backup

    • getBoolean

      public static boolean getBoolean​(String key, boolean backup)
      Returns the boolean at the given key. If this table does not have a value for that position, then the given backup value will be returned.
      Parameters:
      key - the key
      backup - the value to return if none exists in the table
      Returns:
      either the value in the table, or the backup

    • getFloat

      public static float getFloat​(String key, float backup)
      Returns the float at the given key. If this table does not have a value for that position, then the given backup value will be returned.
      Parameters:
      key - the key
      backup - the value to return if none exists in the table
      Returns:
      either the value in the table, or the backup

    • getLong

      public static long getLong​(String key, long backup)
      Returns the long at the given key. If this table does not have a value for that position, then the given backup value will be returned.
      Parameters:
      key - the key
      backup - the value to return if none exists in the table
      Returns:
      either the value in the table, or the backup